U.S. patent application number 12/629966 was filed with the patent office on 2011-06-09 for systems and methods for heating intake air during cold hcci operation.
This patent application is currently assigned to GM GLOBAL TECHNOLOGY OPERATIONS, INC.. Invention is credited to Amanpal S. Grewal, Vijay Ramappan, Jonathan T. Shibata.
Application Number | 20110132317 12/629966 |
Document ID | / |
Family ID | 44080762 |
Filed Date | 2011-06-09 |
United States Patent
Application |
20110132317 |
Kind Code |
A1 |
Ramappan; Vijay ; et
al. |
June 9, 2011 |
SYSTEMS AND METHODS FOR HEATING INTAKE AIR DURING COLD HCCI
OPERATION
Abstract
A system for controlling intake airflow of an engine includes a
mode determination module, a throttle valve control module, and a
valve actuation module. The mode determination module generates a
mode signal based on an engine speed signal and an engine load
signal. The mode signal indicates one of a spark ignition mode and
a homogeneous charge compression ignition mode. The throttle valve
control module generates a valve control signal based on the mode
signal, a temperature signal, and a plurality of valve position
signals that indicate positions of first and second throttle
valves. The throttle valve control module controls the positions of
the first and second throttle valves to regulate flow rates of
intake air into an intake manifold of the engine via a heat
exchanger based on the valve control signal. The valve actuation
module actuates the first and second throttle valves based on the
valve control signal.
Inventors: |
Ramappan; Vijay; (Novi,
MI) ; Shibata; Jonathan T.; (Whitmore Lake, MI)
; Grewal; Amanpal S.; (Novi, MI) |
Assignee: |
GM GLOBAL TECHNOLOGY OPERATIONS,
INC.
Detroit
MI
|
Family ID: |
44080762 |
Appl. No.: |
12/629966 |
Filed: |
December 3, 2009 |
Current U.S.
Class: |
123/295 ;
123/436; 123/556 |
Current CPC
Class: |
F02B 2075/125 20130101;
F02D 41/3035 20130101; F02D 13/0207 20130101; Y02T 10/12 20130101;
F02D 41/0002 20130101; F02D 2200/0404 20130101; F02B 1/12 20130101;
F02M 31/07 20130101; F02D 2200/021 20130101; F02B 17/005 20130101;
Y02T 10/40 20130101; F02D 41/064 20130101 |
Class at
Publication: |
123/295 ;
123/436; 123/556 |
International
Class: |
F02B 17/00 20060101
F02B017/00; F02M 7/00 20060101 F02M007/00; F02G 5/00 20060101
F02G005/00 |
Claims
1. A system for an engine comprising: a mode determination module
that generates a mode signal based on an engine speed signal and an
engine load signal, wherein the mode signal indicates one of a
spark ignition (SI) mode and a homogeneous charge compression
ignition (HCCI) mode; a throttle valve control module that
generates a valve control signal based on the mode signal, a
temperature signal, and a plurality of valve position signals that
indicate positions of a first throttle valve and a second throttle
valve, wherein the throttle valve control module controls positions
of: the first throttle valve to regulate a first flow rate of
intake air out of the first throttle valve and into an intake
manifold of the engine based on the valve control signal; and the
second throttle valve to regulate a second flow rate of intake air
through a heat exchanger and into the intake manifold based on the
valve control signal; and a valve actuation module that actuates
the first throttle valve and the second throttle valve based on the
valve control signal.
2. The system of claim 1, further comprising: an engine speed
sensor that generates the engine speed signal; and a mass airflow
sensor that generates the engine load signal.
3. The system of claim 1, wherein the temperature signal is
generated based on at least one of an engine coolant temperature
signal, an intake air temperature signal, a combustion chamber
temperature signal, and an engine oil temperature signal.
4. The system of claim 1, further comprising: a first throttle
position sensor that detects a position of the first throttle valve
and generates a first valve position signal; and a second throttle
position sensor that detects a position of the second throttle
valve and generates a second valve position signal, wherein the
plurality of valve position signals comprise the first valve
position signal and the second valve position signal.
5. The system of claim 1, wherein the heat exchanger transfers heat
from an exhaust of the engine to the intake air flowing through the
heat exchanger.
6. The system of claim 1, wherein the throttle valve control module
directs the intake air out of the first throttle valve into the
intake manifold via the valve actuation module and the first
throttle valve when the temperature signal is less than a
predetermined temperature, and wherein the throttle valve control
module directs the intake air from the heat exchanger into the
intake manifold via the valve actuation module and the second
throttle valve when the temperature signal is less than the
predetermined temperature.
7. The system of claim 6, further comprising a mode enablement
module that enables the HCCI mode based on the mode signal and the
temperature signal.
8. The system of claim 6, wherein the valve actuation module
regulates the first throttle valve and the second throttle valve to
respective predetermined positions when the mode signal indicates
the HCCI mode.
9. The system of claim 6, wherein the valve actuation module
generates a first actuation signal to actuate the first throttle
valve and a second actuation signal to actuate the second throttle
valve based on the plurality of valve position signals.
10. The system of claim 6, wherein the valve actuation module
regulates: the first throttle valve to set the first flow rate to a
first predetermined value; and the second throttle valve to set the
second flow rate to a second predetermined value.
11. A method of controlling intake airflow of an engine,
comprising: generating a mode signal based on an engine speed
signal and an engine load signal; indicating one of a spark
ignition (SI) mode and a homogeneous charge compression ignition
(HCCI) mode via the mode signal; generating a valve control signal
based on the mode signal, a temperature signal, and a plurality of
valve position signals that indicate positions of a first throttle
valve and a second throttle valve; controlling positions of: the
first throttle valve to regulate a first flow rate of intake air
out of the first throttle valve and into an intake manifold of the
engine based on the valve control signal; and the second throttle
valve to regulate a second flow rate of intake air through a heat
exchanger and into the intake manifold based on the valve control
signal; and actuating the first throttle valve and the second
throttle valve based on the valve control signal.
12. The method of claim 11, further comprising: generating the
engine speed signal via an engine speed sensor; and generating the
engine load signal via a mass airflow sensor.
13. The method of claim 11, further comprising generating the
temperature signal based on at least one of an engine coolant
temperature signal, an intake air temperature signal, a combustion
chamber temperature signal, and an engine oil temperature
signal.
14. The method of claim 11, further comprising: detecting a
position of the first throttle valve via a first throttle position
sensor; generating a first valve position signal based on the
position of the first throttle valve; detecting a position of the
second throttle valve via a second throttle position sensor;
generating a second valve position signal based on the position of
the second throttle valve; and comprising the first valve position
signal and the second valve position signal as the plurality of
valve position signals.
15. The method of claim 11, further comprising transferring heat
from an exhaust of the engine to the intake air flowing through the
heat exchanger.
16. The method of claim 11, further comprising regulating the first
throttle valve and the second throttle valve to maintain
predetermined temperature, the first flow rate, and the second flow
rate.
17. The method of claim 16, further comprising enabling the HCCI
mode based on the mode signal and the temperature signal.
18. The method of claim 16, further comprising regulating the first
throttle valve and the second throttle valve to respective
predetermined positions when the mode signal indicates the HCCI
mode.
19. The method of claim 16, further comprising generating a first
actuation signal to actuate the first throttle valve and a second
actuation signal to actuate the second throttle valve based on the
plurality of valve position signals.
20. The method of claim 16, further comprising regulating: the
first throttle valve to set the first flow rate to a first
predetermined value; and the second throttle valve to set the
second flow rate to a second predetermined value.
Description
FIELD
[0001] The present disclosure relates to engine control systems,
and more particularly to engine control systems for engines
operating in spark ignition and homogenous charge compression
ignition modes.
BACKGROUND
[0002] The background description provided herein is for the
purpose of generally presenting the context of the disclosure. Work
of the presently named inventors, to the extent it is described in
this background section, as well as aspects of the description that
may not otherwise qualify as prior art at the time of filing, are
neither expressly nor impliedly admitted as prior art against the
present disclosure.
[0003] An internal combustion engine (ICE) may be operated in a
spark ignition (SI) mode and a homogeneous charge compression
ignition (HCCI) mode for fuel efficiency and increased engine
power. In the SI mode, an air/fuel mixture may be ignited by spark
plugs in cylinders of the ICE. In the HCCI mode, an air/fuel
mixture may be ignited through compression without ignition by
spark plugs. The HCCI mode is more efficient than the SI mode
because the HCCI mode enables the ICE to operate with leaner
air/fuel mixtures than when in the SI mode.
[0004] The HCCI mode generates a flameless release of energy with a
lean air/fuel mixture by compressing the air/fuel mixture to a
point of auto-ignition. The HCCI mode can provide improved fuel
economy and generate lower emission levels than the SI mode.
However, since there is no direct initiator of combustion, the
ignition process may be inherently challenging to control.
[0005] For example, combustion during the HCCI mode may be
controlled based on temperature. The temperature may be based on an
engine coolant temperature (ECT) signal from an ECT sensor. During
a cold start of the ICE, the HCCI mode may be disabled until the
ECT signal is greater than or equal to a predetermined temperature.
Enabling the HCCI mode during the cold start may cause an unstable
and degraded auto ignition.
[0006] During the HCCI mode, if the air/fuel mixture is ignited by
compression before the predetermined temperature is reached, noise,
damage to engine components, misfires, and/or an engine stall may
occur. This increases emissions and reduces drivability of the ICE.
For the above reasons, the HCCI mode may be delayed until the ICE
is heated to the predetermined temperature.
SUMMARY
[0007] In one embodiment, a system is provided that includes a mode
determination module, a throttle valve control module, and a valve
actuation module. The mode determination module generates a mode
signal based on an engine speed signal and an engine load signal.
The mode signal indicates one of a spark ignition (SI) mode and a
homogeneous charge compression ignition (HCCI) mode. The throttle
valve control module generates a valve control signal based on the
mode signal, a temperature signal, and a plurality of valve
position signals that indicate positions of a first throttle valve
and a second throttle valve. The throttle valve control module
controls positions of the first throttle valve to regulate a first
flow rate of intake air out of the first throttle valve and into an
intake manifold of the engine based on the valve control signal.
The throttle valve control module controls positions of the second
throttle valve to regulate a second flow rate of the intake air
through a heat exchanger and into the intake manifold based on the
valve control signal. The valve actuation module actuates the first
throttle valve and the second throttle valve based on the valve
control signal.
[0008] In other features, a method of controlling intake airflow of
an engine is provided. The method includes generating a mode signal
based on an engine speed signal and an engine load signal. The mode
signal indicates one of a SI mode and a HCCI mode via the mode
signal. A valve control signal is generated based on the mode
signal, a temperature signal, and a plurality of valve position
signals that indicate positions of a first throttle valve and a
second throttle valve. Positions of the first throttle valve are
controlled to regulate a first flow rate of intake air out of the
first throttle valve and into an intake manifold of the engine
based on the valve control signal. Positions of the second throttle
valve are controlled to regulate a second flow rate of the intake
air through a heat exchanger and into the intake manifold based on
the valve control signal. The first throttle valve and the second
throttle valve are actuated based on the valve control signal.
[0009] Further areas of applicability of the present disclosure
will become apparent from the detailed description provided
hereinafter. It should be understood that the detailed description
and specific examples are intended for purposes of illustration
only and are not intended to limit the scope of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present disclosure will become more fully understood
from the detailed description and the accompanying drawings,
wherein:
[0011] FIG. 1 is a functional block diagram of an exemplary engine
control system in accordance with an embodiment of the present
disclosure;
[0012] FIG. 2 is a functional block diagram of a dual intake air
system in accordance with an embodiment of the present disclosure;
and
[0013] FIG. 3 illustrates a method of controlling intake airflow of
an engine in accordance with an embodiment of the present
disclosure.
DETAILED DESCRIPTION
[0014] The following description is merely exemplary in nature and
is in no way intended to limit the disclosure, its application, or
uses. For purposes of clarity, the same reference numbers will be
used in the drawings to identify similar elements. As used herein,
the phrase at least one of A, B, and C should be construed to mean
a logical (A or B or C), using a non-exclusive logical or. It
should be understood that steps within a method may be executed in
different order without altering the principles of the present
disclosure.
[0015] As used herein, the term module refers to an Application
Specific Integrated Circuit (ASIC), an electronic circuit, a
processor (shared, dedicated, or group) and memory that execute one
or more software or firmware programs, a combinational logic
circuit, and/or other suitable components that provide the
described functionality.
[0016] An engine control system according to the present disclosure
may operate an ICE in a SI mode and a HCCI mode. The HCCI mode may
reduce fuel consumption because the HCCI mode may initiate ignition
through compression with a leaner air/fuel mixture than when in the
SI mode. Conditions for enabling the HCCI mode may be satisfied
based on a relationship between an engine speed signal and an
engine load signal. For example only, a first condition may be
satisfied when the engine speed signal is within a first
predetermined range. As another example, a second condition may be
satisfied when the engine load signal is within a second
predetermined range. The engine control system may operate the ICE
in the SI mode when the HCCI mode is disabled.
[0017] The ICE may be a direct injection gasoline engine and may be
selectively operated in a stratified operating mode. To operate in
the stratified operating mode, fuel injectors inject fuel into a
selected area of a combustion chamber before and close in time to
an ignition event. A remainder of the combustion chamber may be
filled with a leaner air/fuel mixture than the air/fuel mixture in
the selected area. This provides a stoichiometric charge near a
spark plug, which causes an air/fuel mixture to ignite easily and
burn quickly and smoothly. The stratified operating mode may
provide a leaner air/fuel mixture than when in a homogeneous
operating mode. Consequently, the stratified operating mode may
minimize engine emissions and fuel consumption losses.
[0018] The embodiments of the present disclosure provide techniques
for controlling intake air temperature and airflow rate during cold
start and/or warm-up events of an engine. The techniques may reduce
pumping losses and provide a lean air/fuel mixture during the HCCI
mode. A lean air/fuel mixture may be provided by adjusting an
intake airflow rate and a fueling rate. The intake airflow rate and
the fueling rate may be controlled by, for example, engine throttle
control valves and a fuel injection system.
[0019] The techniques may also reduce an amount of time associated
with enabling the HCCI mode during the cold start event of the
engine. A use of heated intake air enables a transition from the SI
mode to the HCCI mode sooner than a non-use of the heated intake
air. The earlier the HCCI mode is enabled, the better the fuel
efficiency of the engine.
[0020] In FIG. 1, an exemplary engine control system 100 of a
vehicle is shown. The engine control system 100 may include an
engine 102, a dual intake air system 104, and an exhaust system
105. The dual intake air system 104 enables the engine 102 to be
operated in the HCCI mode early on in a cold start event of the
engine 102 by preheating intake air before being received by the
engine 102. Thermal energy is transferred from an exhaust system
105 of the engine 102 to the intake air using a heated air intake
path. An example of the heated air intake path is described in FIG.
2.
[0021] The dual intake air system 104 includes an engine control
module (ECM) 106 with an intake air control module 108, a heat
exchanger 110, a first throttle valve (cold throttle valve) 112,
and a second throttle valve (hot throttle valve) 114. The intake
air control module 108 controls intake airflow by actuating the
throttle valves 112, 114 based on engine temperature, engine load,
and engine speed. The engine temperature may refer to engine oil
temperature, engine coolant temperature, intake air temperature,
and/or combustion chamber temperature.
[0022] The first throttle valve 112 may be equipped with a throttle
position sensor (TPS) 116. The TPS 116 may generate a first valve
position signal VP1 for the first throttle valve 112. The second
throttle valve 114 may also be equipped with a separate TPS 118.
The TPS 118 may generate a second valve position signal VP2 for the
second throttle valve 114. The intake air control module 108 may
monitor the position of the throttle valves 112, 114 using one or
more of the TPSs 116,118. The intake air may be drawn into the
engine 102 to provide an engine operating condition that is
conducive to HCCI mode enablement during cold start and/or warm-up
events of the engine 102. The engine operating condition may refer
to when the engine temperature is greater than or equal to a
predetermined temperature (e.g., 90-95.degree. C.).
[0023] The dual intake air system 104 may include a mass airflow
(MAF) sensor 122, an intake air temperature (IAT) sensor 126, and a
manifold absolute pressure (MAP) sensor 128. During engine
operation, the intake air passes through an air filter 120 and by
the MAF sensor 122. The MAF sensor 122 generates a MAF signal
AirFlow that indicates a rate of airflow through the MAF sensor
122. The intake air is drawn into an intake manifold 124 based on
positions of the throttle valves 112, 114.
[0024] The IAT sensor 126 may detect temperature of the intake air
that is drawn into the intake manifold 124. The IAT sensor 126 may
generate an IAT signal AirTemp. The IAT sensor 126 may be located
in the intake manifold 124 and generate the IAT signal AirTemp
based on an intake air temperature. The MAP sensor 128 may detect
an air pressure within the intake manifold 124 and generate a MAP
signal MfdPres. The MAP sensor 128 may be positioned in the intake
manifold 124. The MAP signal MfdPres indicates the air pressure in
the intake manifold 124.
[0025] The intake air from the intake manifold 124 is drawn into
cylinders of the engine 102 through an intake valve 132. Although
the engine 102 is shown as having a single representative cylinder
130, the engine 102 may include any number of cylinders. The ECM
106 may control an amount of fuel injected by a fuel injection
system 134. The fuel injection system 134 may inject fuel into the
intake manifold 124 at a central location or may inject fuel into
the intake manifold 124 at multiple locations, such as near the
intake valve 132 of each of the cylinders of the engine 102.
Alternatively, the fuel injection system 134 may inject fuel
directly into the cylinders of the engine 102. Injected fuel mixes
with received air and creates an air/fuel mixture in the cylinder
130.
[0026] The ECM 106 may include an engine speed sensor 140, a spark
control module 136, and a lift control module 148. The engine speed
sensor 140 may generate an engine speed signal RPM that indicates a
speed of the engine 102. The speed may refer to a rotational speed
of a crankshaft in revolutions per minute (RPM). The rotational
speed is generated via combustion of the air/fuel mixture in the
cylinder 130. A piston (not shown) within the cylinder 130
compresses the air/fuel mixture. The spark control module 136 may
energize a spark plug 138 in the cylinder 130 to ignite the
air/fuel mixture. The timing of the ignition may be based on a time
when the piston is at its topmost position, referred to as top dead
center (TDC).
[0027] The piston expels exhaust gas through an exhaust valve 142.
The exhaust valve 142 may be controlled by an exhaust camshaft 144,
while the intake valve 132 may be controlled by an intake camshaft
146. In various implementations, multiple intake camshafts may
control multiple intake valves per cylinder and/or may control
intake valves of multiple banks of cylinders. Similarly, multiple
exhaust camshafts may control multiple exhaust valves per cylinder
and/or may control exhaust valves for multiple banks of cylinders.
The lift control module 148 may command switching of the intake and
exhaust valves 132, 142 between a high and low lift states. For
example, the lift control module 148 may transition between two
discrete valve states (e.g., the low-lift state and the high-lift
state) on the intake and/or exhaust valves 132, 142.
[0028] The exhaust gas is discharged out of the engine 102 via an
exhaust manifold 150. The exhaust manifold 150 may include a
catalytic converter 152 to remove particulate matter from the
exhaust gas. The exhaust manifold 150 may provide a source of heat
for the heat exchanger 110. For example, the heat exchanger 110 may
be positioned over the exhaust manifold 150 so that heat from the
exhaust manifold 150 may be transferred to the heat exchanger
110.
[0029] The dual intake air system 104 may also include an engine
coolant temperature (ECT) sensor 154 to detect the engine
temperature. The ECT signal EngCTemp may be generated by the ECT
sensor 154. The ECT sensor 154 may be located within the engine 102
or at other locations where the coolant is circulated, such as a
radiator (not shown).
[0030] In FIG. 2, an exemplary dual intake air system 104 of the
engine control system 100 is shown. The dual intake air system 104
may include the intake air control module 108, the heat exchanger
110, the first throttle valve 112, and the second throttle valve
114. The intake air control module 108 may include a mode
determination module 200, a throttle valve control module 202, a
valve actuation module 204, and a mode enablement module 206.
[0031] The mode determination module 200 may receive signals from
sensors 208. The sensors 208 may include the MAF sensor 122, the
IAT sensor 126, the engine speed sensor 140, the ECT sensor 154, an
engine oil temperature sensor 210, and a combustion chamber
temperature sensor 212. The engine oil temperature sensor 210 may
generate an engine oil temperature signal OilTemp that indicates a
temperature of the engine oil. The combustion chamber temperature
sensor 212 may generate a combustion chamber temperature signal
CCTemp that indicates a temperature of a combustion chamber.
[0032] The mode determination module 200 receives the engine speed
signal RPM from the engine speed sensor 140 and the MAF signal
AirFlow from the MAF sensor 122. The mode determination module 200
generates a mode signal that indicates one of the SI and HCCI modes
based on the engine speed signal RPM and an engine load signal
LOAD. The engine load signal LOAD may be generated based on the MAF
signal AirFlow.
[0033] The throttle valve control module 202 receives the mode
signal and generates a valve control signal based on the mode
signal, a temperature signal, and the first and second valve
position signals VP1, VP2. The temperature signal may be determined
based on at least one of the engine coolant temperature signal
EngCTemp, the intake air temperature signal AirTemp, the engine oil
temperature signal OilTemp, and the combustion chamber temperature
signal CCTemp. Additionally, the temperature signal may be modeled
based on other engine parameters, such as an engine load, an engine
torque, and an engine speed.
[0034] The valve actuation module 204 actuates the throttle valves
112, 114 based on the valve control signal. Positions of the
throttle valves 112, 114 are adjusted to provide intake air
temperature for enablement of the HCCI mode. For example, the first
throttle valve 112 may be closed to force intake air to pass
through a first air conduit 214. The intake air may be heated by
the heat exchanger 110. The second throttle valve 114 may be opened
to direct the intake air into the intake manifold 124 via a second
air conduit 216. The first and second throttle valves 112, 114 may
be regulated such that the intake air temperature entering the
intake manifold 124 is set to predetermined temperature for the
enablement of the HCCI mode.
[0035] The mode enablement module 206 receives the mode signal and
the temperature signal and enables the HCCI mode based on the mode
signal and the temperature signal. For example, the engine 102 may
be operated in the HCCI mode when the mode signal indicates the
HCCI mode and when the temperature signal is greater than or equal
to a predetermined temperature.
[0036] In FIG. 3, a method of controlling intake airflow of an
engine for enablement of the HCCI mode is shown. Although the
following steps are primarily described with respect to the
embodiments of FIGS. 1-2, the steps may be modified to apply to
other embodiments of the present disclosure. Control of a control
module such as the intake air control module 108 of FIG. 1 may
perform the following steps.
[0037] The method may begin at step 300. In step 302, the mode
enablement module 206 may initially enable the SI mode, which may
be a default mode for the engine 102. In step 304, the valve
actuation module 204 may initially regulate the first throttle
valve 112 to a partially open position and the second throttle
valve 114 to a partially closed position. This allows the intake
air to be drawn into the intake manifold 124 through both a first
intake air path 215 and a second intake air path 217 to provide
predetermined temperature and airflow rate for enablement of the
HCCI mode.
[0038] In step 306, the mode determination module 200 receives the
engine speed signal RPM from the engine speed sensor 140 and the
MAF signal AirFlow from the MAF sensor 122. The engine load signal
LOAD may be generated based on the MAF signal AirFlow.
[0039] In step 308, control may proceed to step 310 when the engine
speed signal RPM is within a first predetermined range, otherwise
control may return to step 306. In step 310, control may proceed to
step 312 when the engine load signal LOAD is within a second
predetermined range, otherwise control may return to step 306. The
mode determination module 200 determines whether the engine 102 is
capable of enabling the HCCI mode based on the engine speed signal
RPM and the engine load signal LOAD.
[0040] In step 312, the mode determination module 200 generates a
mode signal that indicates one of the SI and HCCI modes based on
the engine speed signal RPM and the engine load signal LOAD. The
HCCI mode is enabled when the mode signal indicates the HCCI mode
and when an engine temperature is greater than a predetermined
temperature. In other words, although the mode signal indicates the
HCCI mode, an enablement of the HCCI mode is delayed until a
temperature signal of the engine 102 is greater than or equal to a
predetermined temperature. Therefore, the engine 102 may be
operated in the SI mode until the HCCI mode is enabled based on the
temperature signal.
[0041] In step 314, the throttle valve control module 202 may
receive the temperature signal. The temperature signal may be
determined based on at least one of the engine coolant temperature
signal EngCTemp, the intake air temperature signal AirTemp, the
engine oil temperature signal OilTemp, and the combustion chamber
temperature signal CCTemp. For example only, the temperature signal
TEMP may be defined as provided in expression 1.
TEMP=F{EngCTemp,AirTemp,OilTemp,CCTemp} (1)
EngCTemp is an engine coolant temperature. AirTemp is an intake air
temperature. OilTemp is an engine oil temperature. CCTemp is a
combustion chamber temperature.
[0042] In step 316, control may proceed to step 318 when the
temperature signal is less than the predetermined temperature,
otherwise control may proceed to step 324. For example, if the
temperature signal is greater than or equal to the predetermined
temperature and the mode signal indicates the HCCI mode, the HCCI
mode may be enabled for the engine 102 without delay. Enablement of
the HCCI mode may be delayed while the temperature signal is less
than the predetermined temperature.
[0043] In step 318, the throttle valve control module 202 receives
the first and second valve position signals VP1, VP2. The valve
position signals VP1, VP2 may be received from the TPSs 116, 118
for the throttle valves 112, 114 respectively. The valve position
signals VP1, VP2 correspond to positions of the throttle valves
112, 114.
[0044] In step 320, the throttle valve control module 202 may
generate a valve control signal based on the mode signal, the
temperature signal, and the throttle valve position signals. The
throttle valve control module 202 controls the amount of the intake
air that is drawn into the intake manifold 124 and the amount of
the intake air that is directed to the heat exchanger 110.
[0045] For example, a portion or all of the intake air may be
directed through the heat exchanger 110 based on positions of the
first and second throttle valves 112, 114. The intake air may be
directed to the intake manifold 124 through the intake air paths
215, 217. The throttle valve control module 202 may regulate a
first flow rate of air in the first intake air path 215 and a
second flow rate of air in the second intake air path 217 by
controlling the positions of the first and second throttle valves
112, 114.
[0046] The positions of the first and second throttle valves 112,
114 may be set based on a function of engine coolant and intake air
temperatures. For example only, the valve control signal Vctrl may
be defined as provided in expression 2.
Vctrl=F{ECT,IAT} (2)
[0047] ECT is an engine coolant temperature. IAT is an intake air
temperature. Although the engine coolant temperature and the intake
air temperature are shown in expression 2, the valve control signal
V.sub.ctrl may be a function of other engine temperatures, such as
an engine oil temperature and a combustion chamber temperature.
[0048] In step 322, the valve actuation module 204 receives the
valve control signal and generates first and second actuation
signals based on the valve control signal. The first actuation
signal may be used to actuate the first throttle valve 112. The
second actuation signal may be used to actuate the second throttle
valve 114. For example only, the first throttle valve 112 may be
set in a fully closed position and the second throttle valve 114
may be set in a fully open position. This allows air to flow
sequentially through the first air conduit 214, the heat exchanger
110, the second air conduit 216, and the second throttle valve 114.
The intake air is drawn into the intake manifold 124 via the intake
air paths 215, 217.
[0049] Additionally, the throttle valves 112, 114 may be opened and
closed based on the valve position signals VP1, VP2 from the TPSs
116, 118. The throttle valves 112, 114 may be partially and/or
gradually opened and closed to mix hot and cold air to provide
predetermined or set temperature. The throttle valve control module
202 receives the valve position signals VP1, VP2 and generates the
valve control signal based on the valve position signals VP1, VP2.
The valve actuation module 204 receives the valve control signal
and change valve positions for the throttle valves 112, 114 based
on the valve control signal.
[0050] In step 324, the mode enablement module 206 disables the SI
mode to allow the engine 102 to operate in the HCCI mode. In step
326, the mode enablement module 206 enables the HCCI mode based on
the mode signal and the temperature signal. The HCCI mode may be
enabled when the mode signal indicates the HCCI mode and the
temperature signal is greater than or equal to the predetermined
temperature.
[0051] In step 328, the valve actuation module 204 may regulate the
first and second throttle valves 112, 114 to maintain the intake
air to predetermined temperature and airflow rate for the enabled
HCCI mode. The intake air may be drawn into the intake manifold 124
via the intake air paths 215, 217. Control may end at step 330.
[0052] The above-described steps are meant to be illustrative
examples; the steps may be performed sequentially, synchronously,
simultaneously, continuously, during overlapping time periods or in
a different order depending upon the application.
[0053] The broad teachings of the disclosure can be implemented in
a variety of forms. Therefore, while this disclosure includes
particular examples, the true scope of the disclosure should not be
so limited since other modifications will become apparent to the
skilled practitioner upon a study of the drawings, the
specification, and the following claims.
* * * * *